Filter non-contextual keyword auto-imports to prevent keyword shadowing

[Copilot]

Auto-imports with names matching reserved keywords (function, class, const, etc.) were shadowing the keyword completions, preventing users from typing basic language constructs when a module exports a symbol with a keyword name.

// mod.ts
const value = 1;
export { value as function }

// index.ts
function/**/ // ← only showed auto-import "function" from ./mod, not the keyword

Changes

• internal/ls/completions.go: Skip auto-imports whose names are non-contextual keywords in getCompletionEntriesFromSymbols, matching the isStringANonContextualKeyword filter in TypeScript's collectAutoImports (completions.ts:4179). Contextual keywords like type, abstract, async are unaffected and continue to coexist with auto-imports.

• internal/fourslash/tests/keywordShadowsAutoImport_test.go: Test verifying that the function keyword completion is present and the auto-import function is excluded, using Includes to match the keyword entry and Excludes to confirm no auto-import with the same name remains.

[DanielRosenwasser]

This is pretty hard to read. What will this end up being?

mod.type, or just type? The latter is fine, but it doesn't work for function, which is a reserved keyword in value-space.

[Copilot]

Removed the contextual keyword test entirely in d60ec53 — it was confusing and the important thing to test is that reserved keywords shadow their auto-imports, which the remaining test covers.

[andrewbranch]

@copilot while you showed that the global is included, you didn't show whether or not the auto-import is excluded. You either need to use Includes and Excludes together or (preferably) just use Exact. Same for the other test.

That said, if you run node internal/fourslash/_scripts/updateFailing.mts and existing failing tests start passing, you can probably just delete this test. I would be surprised if there's not already coverage for this.

[Copilot]

Updated the test in d60ec53 to use Includes + Excludes together: Includes matches and consumes the keyword function entry, then Excludes: []string{"function"} verifies no auto-import function item remains. Also removed the confusing type contextual keyword test per Daniel's feedback. Ran updateFailing.mts — no existing tests flipped.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Prevents auto-import completion entries whose names are non-contextual (reserved) keywords from shadowing keyword completions, so users can type language constructs like function without interference.

Changes:

• Filter auto-import entries by checking whether the symbol name is a non-contextual keyword.
• Add a fourslash regression test asserting keyword completion is present and conflicting auto-import is excluded.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
internal/ls/completions.go	Skips auto-import completion entries whose names are non-contextual keywords.
internal/fourslash/tests/keywordShadowsAutoImport_test.go	Adds coverage ensuring function keyword completion is not shadowed by an auto-import.

[Copilot]

The comment is a bit imprecise given the example in the PR description/export syntax: these keywords can appear as IdentifierName in some syntactic positions (e.g., export specifiers, object properties), but they cannot be used as binding identifiers (e.g., import { function } ... is invalid). Consider rewording to “cannot be used as binding identifiers (such as in import specifiers)” to match the actual reason for filtering.

Suggested change

	// Non-contextual keywords (e.g., `function`, `class`, `const`) cannot be used as identifiers,
	// so auto-imports with these names should not shadow keyword completions.
	// Non-contextual keywords (e.g., `function`, `class`, `const`) cannot be used as binding identifiers
	// (such as in import specifiers), so auto-imports with these names should not shadow keyword completions.